Treating-out transformer



May 28, 1935. H. A. ROSE TREATING-OUT TRANSFORMER Filed Dec. 21, 1952 2Sheets-Sheet 1 Gazhode Amperes INVENTOR Herbert A. Rose.

ATTORNEY May 28, 1935. H. A. RosE; 2,003,011

TREATING-OUT TRANSFORMER Filed Dec. 21, 1952 2 Sheets-Sheet 2 BYgi ZATTORNEY Patented May 28, 1935.

UNITED STATES PATENT A oFFiCE l j Westinghouse Electric- & ManufacturingCompany, East Pittsburgh, Pa.,'a corporation of Pennsylvania.

Application December '21, .1932, Serial No; 548,204 3 Claims. ((1175-363) My invention relatesto a treating-out transformer and particularlyto a transformerhaving an auxiliary winding for initiating thecurrentcarrying or main arcs in a rectifier being treated.

In treating-out rectifiers, it is desirable to provide sufficientvoltage to supply the arc drop without any appreciableremainder in orderto' perform the operation economically. However, in treating-outrectifiers, it is frequently found that a potential substantially equalto the arc drop is not suflicient to initiate a'rectifying are even inthe presence of a continuously operating keep-alive arc. According to myinvention, the treating out transformer is provided with an auxiliarywinding capable of producing a voltage sufliciently in excess of thearcvoltage to fiash? the rectifier and start a rectifying arc, after whichthe rectifier may be switched back to the treating out winding forproviding the normal treating out current. Preferably the starting 7winding will be connected to only a portion of the anodes while theremaining anodes will remain connected to the treating-out winding;

Suitable switching equipment may be provided for changing the connectionto thetreating .out winding or the starting winding at the will of theoperator. In order to provide an economical de sign, it is desirablethat the starting winding be provided with a steep regulationcharacteristic suiiicient to reduce its voltage substantially. to thatof the treating-out winding when the starting winding iscarryingcurrent.

I have found that this auxiliary winding may be associated with the ironof the treating'out transformer or in some cases it may mostadvantageously be constructed as a separate transformer and thenassembled as aunit with the main treating-out transformer.

Otherobjects and advantages will be apparent from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich 1 Figure-1 is a schematic view of a treating-out system embodyingmy invention.

Fig. 2 is a similar view showing a modification.

Fig. 3 is a graphic illustration of the potentials applied by thetreating-out transformer, and

Fig. 4 is a View similar to Fig. 2 showing a modification according tomy invention.

The treating-out transformer, according to my invention, comprises asuitable polyphase primary l adapted to be connected to the high tensionline 2 by a suitable circuit breaker 3. As shown, the primary isconnected in delta, each leg of the delta being comprised .of twowinding groups and suitable variable connectors 4 be-,

tween'ithe groups for changing the numberof turns 'in'the deltawindings, and consequently th voltage of the treating-out winding. Y

The secondary winding consistsofa star connected group 6 adapted to -beconnected to the anodes I of the rectifier 8 undergoing treatment. Asuitable keep-alive source I0 is provided for maintaining a keep-alivearc; in the, rectifier 8. A'suitablecurrent limiting resistor 12 .is connected between the mid-point of the secondary winding 6 and therectifier cathode l5. Preferably, the primary I is so adjustedthat thevoltage of the star secondary 6 is sufiicient to supply. the desiredcurrent to the anodes 1 at a voltage substantially equal the arc dropvoltage of the rectifier. This prevents wasting of any material quantityof energy, in the regulating resistor 12.

A suitable high voltage winding 20; preferably single phase, isassociated with'the primary 1 in such a manner that the terminalvoltages of the auxiliary winding 20 may be connected to one or more ofthe anodes I of the rectifier 8. Suitable switches ,Zl may be providedfor connecting the selected anodes either to the auxiliary startingwinding 20 or to the main treating-out winding 6. V

A suitable connection 22 is provided betweenthe mid-point of thetreating-out winding 6, and the starting winding 20. The treat-outwinding 6 may have a substantially flat voltage characteristic on thedifferent taps of the primary, as shown by the'characteristic curves252621 of Fig. 3. However, thestarting winding 20 should have acomparatively steep or drooping characteristic, as

shown by :the characteristiccurve 30 in Fig. 3.

. Inthe operation of ,my device, the keep-alive electrode 32 isenergized by a, suitable auxiliary rectifier I0, preferably connected bya suitable anodes 1 will then'be disconnected from the treatout winding6 and connected to the starting winding 20. The high potential of thiswinding insures the formation of arcs to these anodes which readilycauses pick up of the remaining anodes connected to the treat-outwinding '6. After the anodes connected to the treat-out winding havepicked up, the switches 2| may be operated to connect the anodesoriginally connected to the starting winding to the treat-out winding. 7

The modification shown in Fig. 2 differs from that of Fig. 1 only inthat the starting winding 40 is wound on a separate iron core andprovided with its own primarywi'nding 42.. In some cases, it may bedesirable to construct the starting winding for continuous operation andto connect it permanently to the starter anodes as shown at 45. Theswitch 2| between the anode lead and the treat-out transformer is usedfor connecting the anodes to the treat-out winding 6 tojjcarry fullcurrent without disconnecting the same from the starting winding.Theexceedinglsteep regulation 30 of the flashing winding will cause the'current to divide between the starting winding and the treat-out windinginsuch proportion that the majority of the treat-out current will-besupplied by the treat out winding 6.

I he current supplied by theauxiliary winding 20 maybe regulated ifdesirdby a resistor arrangement 35 in the neutral connection{22;

A further modification(see-Fig} 4) consists in utilizing the tank properas the starting anode. When the tank is used as thestarting anode onlyone end of the auxiliary winding 50 can beconnected to the tank whilethe other end must be attached to the cathode,'thus the auxiliary wind-'ing 50 carries only unidirectional current. -In order to offset thesaturating effect of the direct current in the secondary 50 the core 5|is provided with a suitable air gap 52.

While I have shown and described specific modifications ofmy'invent'ion, it is apparent that changes and modifications can be madetherein without departing from the spirit and scope of my invention. Idesire, therefore, that only such limitations shall be imposed as areembodied in the accompanying claims or asmay be necessitated by thepriorart.

I claim as my invention:

1. A treating out-transformer'for a vapor electric device comprising aprimary winding, a polyphase secondary winding adapted for connection tothe anodes of the vapor electric device, said secondary 'windinghaving aterminal voltage substantially equal to the arc drop of the device, anauxiliary winding in said transformer, said auxiliary windingnormally-havinga "higher voltage than said secondary winding, means forselectively connecting two of the anodes'to either said secondary orsaid auxiliary winding, and a common return connection to said secondarywinding and said auxiliary winding.

2. A treating out transformer for a vaporelectric device comprising aprimary winding, a polyphas e secondary winding adapted forconnection tothe anodes of the vapor electric device, an aux iliary windingin saidtransformer, said auxiliary winding normally having a highervoltage'than said secondary winding, meansfor selectively connecting twoof the anodes to 'either said secondary or said auxiliary winding, aneutral tap in both said secondary and said auxiliary winding and aresistor connectedbetween: said neutral taps for limiting the current insaid auxiliary winding.

3. In a rectifier system, a multi-ancde rectifier, a transformer fortreating out said rectifier er than the arcdrop of the rectifier andmeans for connecting one of said anodes at will to said main winding orsaid auxiliary winding.

la-Ina treating out device for a rectifierhaving 'aplu'rality of anodes,a polyphase transformer, phase windings in said transformer forattachment to said anbdes, voltage adjusting taps in said transformerfor adjusting the voltage appliedtosaid anodes to avalue substantiallyequal to the arcdrop in the rectifier, an auxiliary winding associatedwith said transformer, said auxiliary'winding havinga steep regulationcharacteristic and means for connecting at least one of said anodeseither to'said phase windings or to said auxiliary winding. v

5. A treating out transformer for. a mercury arc rectifier comprising apolyphase secondary having a neutral tap, means for connecting thesecondary, to the rectifier anodes, a tertiary winding in phasefwith oneofthe phases of the secondary winding, said'tertiary having a. steepregulation characteristic and means operable to disconnect an anode fromthe secondary and connect itto .the tertiary.

6. A treating-out transformer for a vapor-electric device comprising, awinding adapted for connection to an alternating current line, a windingadapted for supplying to the anodes of a vapor-electric device apotential of the order of the arc drop in. the device, an auxiliarywinding in said transformer adapted forconnection to the anodes of thevapor electric device and means for limiting the current in saidauxiliary winding.

'7. A system for supplying treating-out current to avapon-electricdevice comprising a winding adapted for supplying treat-out voltage tothe anodes of the device being treated, a winding for producing avoltage in excesss of the treatingout voltage, a switch for connectingat least one of the anodes of the device to either said first or saidsecond winding and means for limiting the current supplied by saidsecond mentioned winding.

8. A'system for supplying treating-out current to a vapor-electricdevice comprising a winding adapted for connection to the anodes of thedevice being treated, a winding for producing a voltage in excess of thetreating-out voltage, a switch-for'connecting at least one of the anodesof the device'to either said first or said second winding and resistancemeans for limiting the currentsupplied by said second mentioned winding.

HERBERT A. ROSE.

